<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    .playBtn {
      font-size: 2rem;
      border-radius: 12px;
      outline: none;
      cursor: pointer;
      transition: all .5s;
    }
    .playBtn:hover {
      background: #333;
      color: #eee;
      transition: all .5s;
    }
  </style>
</head>
<body>
  <button class="playBtn">Click Me</button>
</body>
</html>